Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
From:   Sasha Levin <Alexander.Levin@microsoft.com>
To:     "stable@vger.kernel.org" <stable@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
CC:     Logan Gunthorpe <logang@deltatee.com>,
        Jon Mason <jdmason@kudzu.us>,
        Sasha Levin <Alexander.Levin@microsoft.com>
Subject: [PATCH AUTOSEL for 4.15 106/189] ntb_hw_switchtec: Check for
 alignment of the buffer in mw_set_trans()
Thread-Topic: [PATCH AUTOSEL for 4.15 106/189] ntb_hw_switchtec: Check for
 alignment of the buffer in mw_set_trans()
Thread-Index: AQHTz5g94RiWsAj6lUin796tWIIR3g==
Date:   Mon, 9 Apr 2018 00:18:09 +0000
Message-ID: <20180409001637.162453-106-alexander.levin@microsoft.com>
References: <20180409001637.162453-1-alexander.levin@microsoft.com>
In-Reply-To: <20180409001637.162453-1-alexander.levin@microsoft.com>
Accept-Language: en-US
Content-Language: en-US
received-spf: None (protection.outlook.com: microsoft.com does not designate
 permitted sender hosts)
spamdiagnosticoutput: 1:99
spamdiagnosticmetadata: NSPM
Content-Type: text/plain; charset="iso-8859-1"
Content-Transfer-Encoding: quoted-printable
MIME-Version: 1.0
X-MS-Exchange-CrossTenant-Network-Message-Id: d57f589f-dca4-407f-2db7-08d59daf8bb8
X-MS-Exchange-CrossTenant-originalarrivaltime: 09 Apr 2018 00:18:09.6625
 (UTC)
X-MS-Exchange-CrossTenant-fromentityheader: Hosted
X-MS-Exchange-CrossTenant-id: 72f988bf-86f1-41af-91ab-2d7cd011db47
X-MS-Exchange-Transport-CrossTenantHeadersStamped: DM5PR2101MB1063
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

From: Logan Gunthorpe <logang@deltatee.com>

[ Upstream commit 1e2fd202f8593985cdadca32e0c322f98e7fe7cb ]

With Switchtec hardware, the buffer used for a memory window must be
aligned to its size (the hardware only replaces the lower bits). In
certain circumstances dma_alloc_coherent() will not provide a buffer
that adheres to this requirement like when using the CMA and
CONFIG_CMA_ALIGNMENT is set lower than the buffer size.

When we get an unaligned buffer mw_set_trans() should return an error.
We also log an error so we know the cause of the problem.

Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
Signed-off-by: Jon Mason <jdmason@kudzu.us>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
---
 drivers/ntb/hw/mscc/ntb_hw_switchtec.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/drivers/ntb/hw/mscc/ntb_hw_switchtec.c b/drivers/ntb/hw/mscc/n=
tb_hw_switchtec.c
index ca0334a6b759..fc9ce0a31c04 100644
--- a/drivers/ntb/hw/mscc/ntb_hw_switchtec.c
+++ b/drivers/ntb/hw/mscc/ntb_hw_switchtec.c
@@ -315,6 +315,19 @@ static int switchtec_ntb_mw_set_trans(struct ntb_dev *=
ntb, int pidx, int widx,
 	if (xlate_pos < 12)
 		return -EINVAL;
=20
+	if (!IS_ALIGNED(addr, BIT_ULL(xlate_pos))) {
+		/*
+		 * In certain circumstances we can get a buffer that is
+		 * not aligned to its size. (Most of the time
+		 * dma_alloc_coherent ensures this). This can happen when
+		 * using large buffers allocated by the CMA
+		 * (see CMA_CONFIG_ALIGNMENT)
+		 */
+		dev_err(&sndev->stdev->dev,
+			"ERROR: Memory window address is not aligned to it's size!\n");
+		return -EINVAL;
+	}
+
 	rc =3D switchtec_ntb_part_op(sndev, ctl, NTB_CTRL_PART_OP_LOCK,
 				   NTB_CTRL_PART_STATUS_LOCKED);
 	if (rc)
--=20
2.15.1